Method and apparatus for producing printing plates



E. J. TILTON 2,191,945 METHOD AND APPARATUS FOR PRODUCING PRINTIiNG PLATES Feb. 27, 1940.

2 Sheets-Sheet 1 Filed June 21, 1937 ELVIN J. TILTON Fig.2

" ATTORNEY.

Feb. 27, 1940. A E; J. TILTON 2,191,945

METHOD APPARATUS FOR PRODUCING PRINTING PLATES Filed June 21, 1937 2 Sheets-Sheet 2 /6 2/ 7 v 7 flg /a figfi 1M 2! ifiga fig a INVENTOR.

ELVIN J. TILTON BY A ATTORNEY.

Patented Feb. 27, 1940 UNITED STATES METHOD AND APPARATUS FOR PRODUCING PRINTING PLATES Elvin J. Tilton, Brownsville, Pa.

Application June 21,

4 Claims.

This invention relates to a method and means ture by the use of a scanning device.

for reproducing a picture or image in a conventional semi-tone on a matrix preparatory to the making of a printing plate, and also to a printing plate made therefrom which has a surface that permits auniform variation in size of the areas of semi-tone. I

A present practice for making a full tone image on a metal printing plate is to project a picture or image onto a sensitized plate and then etch the plate, leaving the untouched surface as the patrix for the matrix to be made therefrom. If a semi-tone reproduction is desired, the projection is screened and considerable difficulty is had in etching satisfactorily the small semi-tone areas. This practice requires expensive projection and photographic equipment as well as elaborate etching accessories, making it impractical for the smaller printing establishments and compelling them to rely upon others for preparing printing plates, which in most cases is unsatisfactory due to delays and expense.

In my invention, an object is to provide a prac' tical and comparatively simple method and a means which reproduces an image or a picture directly on matrix material in aconventional semi-tone. The relatively small semi-tone areas are produced by a means which positively and accurately space indentations in matrix material and the depth of each indentation determines the extent of the individual tonal area or increment of printing surface.

The depth of each indentation is controlled by a scanning device, the type of which is used for photo-telegraphy. United States Patent No. 1,719,621, issued on July 2, 1929, pertains to apparatus which discloses the use of a scanning device for making a printing plate. The plate is made direct from a picture or image by removing the non-printing metal plate area so that the remaining portion constitutes the actual printing surface. For making semi-tone areas, a cutting tool or drill, as a part of the apparatus, is shown, which by intermittent operation removes printing surface area, leaving a printing surface area in relief corresponding to a semi-tone reproduction of the picture. The operability of this apparatus, as well as its practicality in use, is highly problematical for reproducing a semi-tone plate. The need in printing has not been satisfied by the disclosure made in the aforesaid patent, and with this in mind I have developed my invention.

My invention provides a practical method and a means which produces a semi-toned image meeting present day demands directly from a pic- 1937, 'Serial N0. 149,359

The device controls directly the extent of printing or semitonal areas, and a means for producing the tonal areas in substantially spaced relation is provided and is positive in action, inexpensive in construction and simple in operation.

Another object of my invention is to provide a method and means for producing a printing plate having a surface of semi-tone character similar to that produced by the present day expensive screening and etching method.

It is a further object of this invention to provide a printing platein which the semi-tonal areas may be varied in size uniformly so as to increase the actual printing area, thereby producing somewhat of a micro-toning effect.

It is a further and an important object of this invention to provide a method and means for producing a printing plate, which means is comparatively inexpensive'and simple in operation, and which effects a considerablesaving in"print ing plate production cost over present day methods due to the elimination of the costly etched zinc plate now necessary for making a matrix.

Other objects and advantages of the invention will become apparent from the specification and drawings, in which:

Fig. 1 is a diagrammatic view in perspective of an embodiment of my invention;

Fig. 2 is a diagrammatic View illustrating a scanning device and a sensitive means for reproducing the picture or image;

Fig. 3 is an illustration of a device for indenting the matrix in a predetermined fixed relation;

Fig. 4 isanother view of the same device illustrated in Fig. 3;

Fig. 5 is anenlarged View of a tooth or projection for indenting the matrix;

Fig. 6 is aside elevation of the same tooth;

Fig. '7 is a magnification of a plate surface;

8 is a side elevation of the same plate before the printing surface is prepared by shaving; and

Fig. 9 is a magnified illustration of a matrix prepared direct from the pictureor image by my method and means from which is made the plate shown in Figs. 7' and 8.

Referring to Fig. l,- a cylinder i has mounted thereon a photograph 2 and matrix material 3, the cylinder having preferably a metal periphery with a composition center in order to decrease the effect of inertia. The cylinder is mounted for rotation on a rod 4 supported by a frame l and is provided with an internally threaded axial bore. The rod 4 has a threaded surface cooperable with the threads of the bore or the cylinder I so that, upon rotation of the cylinder I, it moves along the rod 4 which is rigidly secured to frame 1. The number of threads per inch determines the tonal lines in one direction in reproduction and any number of threads desired may be provided. For instance, if the reproduction is to be a (SO-line picture, then 60 threads per inch should be used so that for 60 complete rotations of the cylinder I, it moves one inch along the rod 4. The cylinder is driven by a motor 8 which is suitably geared thereto.

The photo-telegraphic device illustrated in Figs. 1 and 2 is an ordinary scanning device which directs a beam of light from a source l onto the picture 2 through a lens ll and has a sensitive photo-electric cell l3 responsive to the intensity of light reflected for controlling the extent of energization of magnet M, the reflected light being directed onto the cell l3 by lens I2. The magnet I4 is operably positioned with relation to the arm l5 for raising the arm which is supported and pivoted by a standard I6. The arm 15 carries an indenting device H. In the illustrative example, a spring 2|] normally positions the arm l5 and device I! relative to the surface of the matrix material 3 so that the indenting device is at maximum penetration, and the magnet M operative to lift the device I! and decrease the penetration. If desired, however, the operation of the spring and magnet may be reversed.

As illustrated in Figs. 3 and 4, the indenting device H is composed of a body 2| having projections I8 spaced corresponding to the semi-tone desired in reproduction. As an example, for a 60- line reproduction, the projections l8 should be spaced approximately of an inch apart. Each projection l8 may be of a circular or polygonal base having converging sides, as illustrated in Figs. 5 and 6. A projection indenting the matrix material to a given depth defines by this depth the extent of the semi-tonal printing area, as will be more fully disclosed, and therefore the projection must be of a shape for providing this relationship.

In operation, a beam of light is directed against the photograph, and for a dark spot on the photograph no elfective reflection is made. Consequently, the magnet l4 does not displace the arm IE or the indenting device I! relative to the matrix material 3, and the projections I8 indent the surface to a maximum degree, corresponding to (a) Fig. 9, and in a predetermined spaced relation. The beam of light traversing a lighter spot causes energization of the magnet l4 in an amount in a direct proportional relationship to the intensity of light reflected. The energization of the magnet displaces the arm l5 proportionally against the action of the spring 20, elevating the indenting device and reducing the depth of indentation as (b), Fig. 9. Upon striking a light spot, the maximum reflection of light is made, energizing magnet l4 so as to displace arm [5 and elevate device I! and to produce substantially no indentation, as (c) Fig. 9, which may be actually no eifective indentation. Modifications may be made in the operation of this device by varying the operation of the scanning device for producing other results.

It is to be noted that as the beam traverses the photograph in lines in one direction by the advance of the cylinder I along the rod 4, the device ll produces indentations positively in a predetermined spaced relation in lines in another direction on the matrix material, so that a conventional uniform lined photograph is made in the two directions corresponding to a semi-toned reproduction. Actually, in the embodiment shown the indentations are spaced along a spiral path on the matrix material with one component or spacing of the indentations being in one dimension of the surface of the matrix, for example, peripherally of its surface, and with the other component or spacing of the indentations being in the other dimension of the surface of the matrix, for example, longitudinally of its surface. The movement of the indenting device is positively in synchronism with the movement of the photograph. Further, my method and apparatus forms directly the semi-tonal printing areas, thus providing practicability and simplicity, and cheapness in production.

Fig. 8 illustrates a printing plate 25 cast from the matrix of Fig. 9, and in preparing the printing surface illustrated in Fig. 7, the plate 25 cast from the matrix 3, Fig. 8, may be dressed down by shaving the projections down to the line d-d, and the resulting tonal areas bear the same relation to each other as the height of the projections from which the areas are made.

Also, less reduction represented by line ee would produce a lighter surface or less printing area, and more reduction represented by line f-f would produce a darker surface or greater printing area, which makes possible a micro-variation in tone over that mad by tonal lines.

Making a matrix of a picture or image by the use of a mechanical device comparatively simple and inexpensive for locating the semi-tonal areas in a predetermined spaced relation, and creating the relative extent of a semi-tonal area by means of a device responsive to a scanning means which defines the area by the depth of indentation in the material. provides a practical method and apparatus for use in a printing establishment. The printing plate is then cast from the matrix and it has surfaces complementary in shape to the indentations of the matrix defining the semi-tonal areas, and the actual printing surface areas are formed by dressing down or shaving the projections to an extent depending upon the result desired. To this my invention is directed. The apparatus as disclosed for illustrating my invention is not to be considered as defining the limit of my invention. I intend to be limited in scope only as defined in the appended claims.

Having thus described my invention, what I claim is:

1. In an apparatus for producing in matrix material a sen1i-toned reproduction of an image, a scanning mechanism arranged for scanning an image to be reproduced in the matrix material by indenting the material, an indenting tool in continuous indenting relation to the matrix and drivingly connected thereto and relatively movable toward and away from that surface of the matrix material which is to be indented, said driving connection between the tool and the matrix material being operative for distributing the indentations along one dimension of the surface of the material, means for effecting relative travel of the tool and the material along the other dimension of the surface of the material in predetermined relation to the operation of the scanning mechanism whereby predetermined distribution of the indentations over the surface of the material is efiected in said two dimensions of the material, and means responsive to the scanning mechanism for effecting relative movement of the tool toward and away from the said surface of the matrix material in predetermined relation to the operation of the scanning mechanism.

2. In an apparatus for producing in matrix material a semi-toned reproduction of an image, a scanning mechanism arranged for scanning an image to be reproduced in the matrix material by indenting the material, an indenting tool relatively movable toward and away from that surface of the material which is to be indented, a plurality of projections on said tool arranged for successive indenting engagement with the matrix material consequent upon said relative movement of the matrix and tool and drivingly connecting the material and tool to effect said relative movement, whereby said indentations are distributed in one dimension of the surface of the matrix material, means operative in predetermined relation to the actuations of the scanning mechanism for effecting a difierent relative travel of the tool and matrix in the direction of another dimension of the surface of the material for distributing the indentations in said other dimension of the surface of the matrix, and means responsive to the scanning mechanism for moving the tool toward and away from the said surface of the matrix in predetermined relation to the actuation of the scanning mechanism.

3. In an apparatus for producing in matrix material a semi-toned reproduction of an image, a scanning mechanism arranged for scanning an image to be reproduced in the matrix material by indenting the material and including a rotatable cylinder for supporting the image, a supporting cylinder arranged for rotation in predetermined relation to the rotation of the first cylinder and arranged for supporting matrix material, an indenting tool rotatable about an axis parallel to the supporting cylinder and having radial projections which are in continuous indenting relation to the matrix and are spaced in accordance with the spacing of the tonal lines to be produced in the matrix material, said tool being relatively eration ofthe scanning mechanism whereby a predetermined distribution of the indentations over the matrix surface is effected, and means operatively associated with the scanning mechanism for effecting relative movement of the indenting tool toward and away from the said surface of the matrix material in predetermined relation to operations of the scanning mechanism.

4. In an apparatus for producing in matrix material a semi-toned reproduction of an image, a scanning mechanism arranged for scanning an image to be reproduced in the matrix material by indenting the material, indenting means arranged for indenting relation to the matrix and relatively movable toward and away from that surface of the matrix material which is to be indented and movable along the surface of the ma terial in one dimension of the matrix, means driven by the matrix material for effecting relative movement of the indenting means along the material in one dimension of the surface of the material, means for effecting relative movement of the indenting means and the matrix material in another dimension of the surface of the material in predetermined relation to the operation of the scanning mechanism whereby predetermined distribution of the indentations over the surface of the material is effected, and means operatively associated with the scanning mechanism for effecting relative movement of the tool toward and. away from the said surface of the material in predetermined relation to the operation of the scanning mechanism.

ELVIN J. THJI'ON. 

